The Readiness Code is a set of 8 bits, each of
which corresponds to one monitored emissions "system" in an OBD-II car. When all
readiness bits show "Passed", it means that all systems have been checked and
have passed
the on-board tests.

Whenever you clear DTC's or remove power from the ECU, all readiness bits will
be set to "fail". Most cars do not have all 8 systems, so as soon as you apply
power again, the bits corresponding to systems that are not actually in the car
will come up "Passed" again.

It takes a variety of specific driving
conditions to "test" all the systems. It can be done in a short time using a
very specific and complicated procedure found in the On Board Diagnostic section
of the Factory Repair Manual for your engine. The alternative is just to drive
the car for 2-3 days. Make sure you include at least one short highway
trip, and your Readiness Bits should all read "Pass" again.

Use [Go
Back]to return to the Controller Information Screen.

As of version 409.0 VAG-COM also Decodes Readiness bits into meaningful data
on modern TDI engines(a VAG-COM exclusive, not even the VAS-5051/5052
does this!):

Notes:

This function is only available on Engine Controllers that are OBD-II compliant
(all 1996 and newer US-Model gasoline engines).

Non-US models and older TDI's may not support this
function even though they are otherwise OBD-II compliant. OBD-I did not require
any "monitors".

12V 2.8L V6 engines may have readiness bits
stored in or near Measuring Block Group 029.

Support for Guided Readiness Scripts. Accessible from the Readiness screen, this function will guide the user
through the process of setting Readiness on those engines which support it.

Note: The Guided Readiness Scripts
require supporting data in Label files. Support in the labels shipping with
Release 704 is very limited. We hope to have most US-model engines covered
in the near future. If you have a specific engine you would like to see
covered and have a written procedure for it, please
contact us.